class Solution {
    public List<String> partitionString(String s) {
        List<String> res = new ArrayList<>();
        Set<String> vis = new HashSet<>();
        String tmp = "";
        /// List 转 String 类
        for (char c : s.toCharArray()) {
            tmp += c; /// 可直接字符串拼接
            /// Set.add返回值 : 添加成功与否的boolean ( 已存在则添加失败 )
            if( vis.add(tmp) ){
                res.add(tmp);
                tmp = "";
            }
        }return res;
    }
}